First Version

js/theme.js

@@ -0,0 +1,44 @@
+/**
+ * Theme Switcher Utility
+ */
+
+// Theme configuration
+const THEMES = ['crimson', 'dark', 'light'];
+
+const THEME_ICONS = {
+    crimson: `<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" width="16" height="16" aria-hidden="true"><path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/></svg>`,
+    dark:    `<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" width="16" height="16" aria-hidden="true"><circle cx="12" cy="12" r="5"/><line x1="12" y1="1" x2="12" y2="3"/><line x1="12" y1="21" x2="12" y2="23"/><line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/><line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/><line x1="1" y1="12" x2="3" y2="12"/><line x1="21" y1="12" x2="23" y2="12"/><line x1="4.22" y1="19.78" x2="5.64" y2="18.36"/><line x1="18.36" y1="5.64" x2="19.78" y2="4.22"/></svg>`,
+    light:   `<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" width="16" height="16" aria-hidden="true"><path d="M12 2c0 0-4 4-4 8a4 4 0 0 0 8 0c0-4-4-8-4-8z"/></svg>`,
+};
+
+const THEME_LABELS = {
+    crimson: 'Switch to dark mode',
+    dark:    'Switch to light mode',
+    light:   'Switch to crimson theme',
+};
+
+let currentTheme = localStorage.getItem('an-theme') || 'crimson';
+
+function applyTheme(theme) {
+    document.documentElement.setAttribute('data-theme', theme);
+    document.querySelectorAll('.theme-toggle').forEach(btn => {
+        btn.innerHTML = THEME_ICONS[theme];
+        btn.setAttribute('title', THEME_LABELS[theme]);
+        btn.setAttribute('aria-label', THEME_LABELS[theme]);
+    });
+    localStorage.setItem('an-theme', theme);
+    currentTheme = theme;
+}
+
+function nextTheme() {
+    const idx = THEMES.indexOf(currentTheme);
+    return THEMES[(idx + 1) % THEMES.length];
+}
+
+// Export for use in other files
+window.ThemeUtils = {
+    THEMES,
+    applyTheme,
+    nextTheme,
+    getCurrentTheme: () => currentTheme,
+};